Rewarming drill

Always good to train. We learn more from real world than we ever could any other way.

Be careful about how cold you let yourself get. Core temp falls a bit and your coordination goes out the window. Can't flick a Bic, can't get a key in a vehicle, etc. That is one good reason to be proficient with something other than a knife on a ferro. A little lower and if you are warmed up too quickly your heart can stop. Lower yet and you feel such euphoria that you won't see the need to get warm. Be careful out there.
 
Yep, interesting drill but can be dangerous as well. What is the temperature of the water? The air? If it's 0 F (-18 C) and any wind you could get frostbite very quickly. And if on the verge of hypothermia getting warmth from a buddy may not be possible.

Synthetics may be good depending on your situation, but if they rip, burn/melt, then they may be the cause of your situation rather than the solution. Wool onm the other hand is extremely durable and below 0 F will actually dry out simply through movement and contact with snow (obviously most useful for the feet). Much more breathable than synthetics it should also dry out much quicker. And cotton canvas/wool won't melt if you have to have a big fire (and of course doesn't stay in the environment for millions of years either like the plastic clothes that fail so readily).

Look up the 'Falling through the Ice, Must start a fire' discussion on wintertrekking. Lots of experienced people weighing in on training for extreme cold and the possibility of falling through. Not that it is necessarily better or that this info is wrong, just that individuals or small groups in different weather may need different training than the military. Basically the main themes are to have ice picks to get out of the water, waterproof fire kit, and possible backup clothes items and shelter.

An interesting bit of information regarding hypothermia is that in a severe case you DO NOT want to warm their limbs as it will possibly send cold blood and air to the heart and kill the victim. This is stage 2 or worse hypothermia. DuxDawg is right, you can become disoriented, and even phase 1 hypothermia you can become sick and have flu-like symptoms. This comes after your inability to stop shivering, and once warmed you may feel like you have a fever.
 
I have a bad history with debates on wool vs. synthetics, so that's not what I'm trying to start again. Just want to clarify a few points that might be helpful. But lets keep in mind that this is a very specific set of methods where fire is not possible, and shows the capabilities of modern materials. I don't think its the end-all-be-all of systems, but I think shows what having the right gear can do. I also think its a better option in most cases than "I'll just light a fire" that won't always work, seems this would have a better chance. Its my opinion, having suffered from hypothermia several times, slow and fast onsets, that the only fire that is going to be useful is one that is already set. A waterproof firekit is not enough, it needs to be a fire, ready to go, with as little help as possible. That is a tall order. In my mind, thats the only fire that counts.

A lot of the hypothermia stuff that gets tossed around is based on really poorly done trials in the 40s, by the kind of people who thought you could "train" out of dehydration. We do have a lot of better info now, and we know a lot more about how the body reacts and starts to shut down.

First aid for hypothermia is "cold fast, warm fast, cold slow, warm slow" worrying about limbs and such only matters for frostbite, and that's a different problem with different concerns. The cold blood thing is a myth. What can happen is that in cases of extreme long exposure hypothermia, in a case where there is severe frostbite, the person can have what is in essence compartment syndrome. The blood that is in the limbs can be toxic to the heart as it contains the breakdown products from the dying tissue. There can be complications from warming up someone too fast, but that is different, has nothing to do with the limbs. The body needs to be able to compensate, and just like heatstroke, as it gets farther from ideal temp, the harder it is for other systems to cope. But if the person has been submerged, so they have lost a lot of heat over a very short period of time, they should be warmed up as quickly as possible, in conditions comfortable to another person. They have no concept of comfort temp, so its easy to over-compensate and over heat them, but there is no real need to warm someone really slowly in that case.

Wool is better than cotton for being wet, this we all know. But modern synthetic materials can drain water out far faster, so for the specific purposes of the re-warming drill, wool would not be a good option. Keep in mind, the layers they are describing are a moving layer, and a sentry layer, most people don't do that. The re-warming drill is also not simulating hypothermia. Its simulating a soaking event, and the goal is to dry everything out before hypothermia sets in. Wool is going to take longer to dry out, for the insulation value, is far heavier. Sure it has its place, but none of these materials are magic. Use the appropriate material for the situation at hand.

I also want to say again, lets not make this a materials debate, stick to the merits of the rewarming drill. I just wanted to clarify a few things about hypothermia that I see passed around very often as truth, which is very old info.
 
Aah the marvels of modern technology.

I can see how with certain clothing systems rewarming with only body heat could work. Much more so than with *traditional gear. If you get even one layer wrong though it could be the difference between life and death so testing is definitely worthwhile.

I don't see a reason not to waterproof your spare clothing/sleeping kit if you are going in to a situation where getting wet is a possibility. Dry bags are worth considering. I think that in the article OP posted they were climbing into fast drying sleeping bags and fast drying puffy jackets that were already dry because they had been left behind on shore. That probably made a significant difference.



*Wool dries much slower than synthetics, you just don't feel the wetness
 
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Synthetics won't dry out faster if they are waterproof, which most winter synthetics are now. And it doesn't matter if you dry out faster if you burn holes in your clothes.

Relying on the body to dry your clothes is simply a bad idea if you can prepare a firemaking situation instead. Wool is a more reliable material, won't soak up the water as quickly, feels warmer to the skin, and has the benefit of drying out through contact with the snow. Keep in mind this should be considered with having an extra set of dry clothes.

The reason this is important is because military drills are not that useful for most people. Different situations, and more often than not, no access to medical and large groups of people. In the wintertrekking community you will find very few people recommend synthetic clothing, especially for falling through the ice.

As for afterdrop, it is not a myth. The results are contested with different beliefs on it. I would like to see where they conclude there is no possible damage from cold blood returning to the heart and brain. It is common sense. If your core is down to 30 C and your limbs are at 25 or so, the change in temperature could very well be the last shock, and that's it. Science often contradicts itself to keep the money coming in, and then later down the road discovers that old information was correct. Kochanski discusses it in his latest book, I'll believe him before some Harvard study.

If one gets hypothermia at -18 C (0F), they will most likely get some level of frostnip or frostbite.
 
With the right system soaked synthetics will dry out much faster than soaked wool. Soaked being the important word here.

I don't make a habit of burning holes in my clothing. Dunno. Fire doesn't really even come into it for a lot of people who are going into the outdoors to do a specific task. It is mostly the people interested in primitive living that want a fire.

There is a case to be made for wool in terms of durability, temperature range comfort and odor resistance. but not in terms of actual technical performance metrics. You can get faster drying, lighter, equally warm synthetic stuff. Which is why hardly anyone uses wool for technical stuff.

Don't get me wrong, wool is a bushcrafters friend. It's good at doing the routine stuff in cold conditions. Technical garments however are what military and climbers use, with good reason I might add, when they need to push faster and further.

Gadgetgeek with regards to the only fire worthwhile being the one that is already started... there is a custom up north where people will leave the fireplaces in wilderness cabins in "just add a match" condition just for that. It is a tradition that has saved the lives of many fishermen who took a tumble through the ice.
 
As my dad used to say, never put the fire out unless the sled is running or you are standing on the dogsled. I've had a fire ready to go in a 4L icecream bucket, and I'm confident that while it might not have saved my life, it was very good to have as I was very very close to done in.

Chignecto, that's not how science works. The scientific method is to try to prove something wrong. Find better evidence to gain better understanding. As for Mors, I'm sure he's a fantastic guy. But even the best can be stuck on info from the past. And they may not have exposure to the most modern materials. All my synthetic gear holds a tiny fraction of its weight in water. The rest just drains out. So I don't waste heat trying to evaporate that water away. With wool, yes its okay when wet, but its not magic, and every gram of water you have to evaporate out of it is calories of energy you are burning. I don't have a lot to spare. As for wool drying in snow, I don't know. I've never tried it, I've heard about rolling in the snow after an immersion to loose some water, but it seems old wifey to me. But I've been wrong before.

As for Cold Shock, Its a matter of thermal mass. the heart and brain are not going to cool as much as the rest of the body, by the time that is a concern, they contain a large portion of the bodies remaining blood, especially the heart. Brain damage is prevented by cooling, so there is limited risk there. A blast of potassium from dead cells however, that'll kill you. Also immersion cold is different than slow cold. Its highly unlikely that you'll get past mild hypothermia and self rescue, so might as well warm up as fast as you can, If you found someone who's cooled slow, its unlikely that you have the heat available to blast them enough to shock their body all that bad. So it kinda doesn't matter. It comes down to thermal mass. I hit frozen water, if I didn't have picks in hand and get a grip, I'm dead. that simple, I don't have enough heat in me to last more than a minute, and I sink. I know some other guys who swim in winter for fun, I'm sure the blood in their muscles is coming back into the body significant cooled, they don't seem to mind.

I will not disagree that if you get hypothermia from exposure to air at -18C you will be at risk of frostbite. I would almost certainly guarantee that due to how long it takes to get hypothermia at that temp, bits will be frozen. At that temp even a little wind can cause frostbite. You wouldn't even need hypothermia. There are stories of guys having their feet frozen through, and not suffering hypothermia. Different problem, different solution, sometimes happens together.
 
I have worn nothing but cotton out in the woods for forty years. "Cotton kills" is a misnomer. "Ignorance kills" is closer to the truth. Recognizing and dealing with situations is what keeps us safe.

There are many ways to quickly start a fire, even after an immersion event. That being said, when soloing on winter through hikes I am likely to build the fire lay and pile up fuel before ice fishing. That is prudence, not a requirement. Starting a fire to me is more dependent on how far from the vehicle I am than anything else.

The rewarming drill article is based on military scenarios and has little to teach us. A bunch of guys piling into a tent is not a likely scenario for most of us. Most that I know solo on almost every trip. If walking to the vehicle is out of the picture, then a fire is always going to be a solo person's next best chance.

Cheers guys! Interesting discussion. And at a timely juncture as our first snow this year is in my forecast this week.
 
upnorth said:
Good article and post thanks.
Click to expand...

agreed! synthetics definitely have some huge advantages in cold/wet environs; it sure is nice to see our troops getting quality garments- when I was in (mid 80's) the garments sucked, low bid garbage- they've come a long way thankfully :)
 
SOP in England was to share a sleeping bag with out clothes
This was the way to warm up a person with hypothermia

No fires
 
Dunno... there is probably more heat to be had from a big hairy half bear, half viking he-man . :D
 
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